Problems involved with evaluating the distance between the rear of a vehicle and rearwardly positioned structures during vehicle back up and parking have long been recognized. Failure to correctly gauge the distance between the rear of the vehicle and a stationary rear wall can result in substantial damage to both the vehicle and to the rear wall. A number of both high-tech and low-tech devices have been suggested in the past to alleviate these problems. By way of example a number of vehicle back up systems involve the use of various kinds of mechanical devices that are mounted on the rear of the vehicle. These types of devices often include numerous interrelated components and are typically subject to mechanical breakdown. Other more sophisticated systems involve the use of video cameras, image sensors and laser devices. These latter types of systems are often quite complex and typically quite expensive.